JPS63278087A - Cleaning device for copying machine - Google Patents

Abstract

PURPOSE:To prevent both of dirt of the machine inside due to unwiped-off toner on a photosensitive body and a defect of cleaning due to paper powder stuck to the front end of a blade by separating the free end of the blade from the photosensitive body after reversing the photosensitive body at the time of terminating copying and reversing the photosensitive body at the time of restart. CONSTITUTION:A blade 2 which has the free end abutted on the surface of a pivotally supported photosensitive body 1 and a retracting means which separates the free end of the blade 2 from the surface of the photosensitive body are provided. A control means is provided to control them so that the free end of the blade 2 is separated from the photosensitive body by the retracting means after reversing of the photosensitive body 1 for a prescribed time at the time of terminating copying and the photosensitive body 1 is reversed again for a prescribed time. Thus, both of a defect of cleaning due to paper powder stuck to the front end of the blade and dirt of the machine inside due to unwiped-off toner 3 on the photosensitive body are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a cleaning device for a copying machine, and more particularly to a blade cleaning device that can be tracted from the surface of a photoreceptor.

In a typical electrophotographic copying machine, the surface of a photosensitive drum that is driven to rotate in one direction is uniformly charged and exposed to light corresponding to the original to form an electrostatic latent image on the photosensitive drum. This static IR latent image is developed with a developer containing toner to become a visible image, and then transferred to transfer paper and the transferred toner image is fixed to obtain a hard copy. . During transfer, most of the toner image carried on the photosensitive drum is transferred onto the transfer paper, but a portion remains on the photosensitive drum and becomes residual toner. Therefore, a cleaning device is usually provided to remove this residual toner in preparation for the next copying cycle.

Typical cleaning devices include a brush cleaning device that removes residual toner with a brush made of a polarized resin that electrostatically attracts toner by friction against the photosensitive drum, and a brush cleaning device that removes residual toner with a brush made of a polarized resin that electrostatically attracts toner by friction with the photosensitive drum, and a brush cleaning device that removes residual toner with a brush made of a resin with a sharp edge such as polyurethane with a hardness of 1165 to 90 degrees. A blade cleaning device that removes residual toner by pressing it against the surface of a rotating photosensitive drum, and a magnetic brush that is used as a cleaning brush by applying a polar bias voltage that electrostatically attracts toner to a magnetic brush similar to that used in developing devices. Brush cleaning devices and the like are known.

Each of these cleaning devices has its advantages and disadvantages, so they are used depending on the purpose.In general copiers, the manufacturing cost is low, the reliability is high, and there is little noise during use. Due to the advantages of
Blade cleaning devices are often used.

The blade cleaning device has a rectangular plate-shaped polyurethane rubber blade whose total length is approximately equal to the width of the photosensitive drum, and by bringing the free edge of the blade into contact with the photosensitive drum with strict linearity, it removes the residue on the photosensitive drum. Toner is being removed. Therefore, if this blade cleaning device is used for a long time, toner, paper dust, etc. will stick to the blade, so in order to maintain good cleaning performance, it is necessary to periodically remove the toner, paper dust, etc. attached to the blade.

Conventionally, in order to remove toner, paper dust, etc. adhering to the cleaning blade, after the copy cycle is completed, the photosensitive drum is rotated in the opposite direction for a short period of time, and then the blade is tracted (retracted) from the photosensitive drum. A blade cleaning device is known in which toner, paper powder, etc. adhering to the blade are splashed off by the reaction at this time.

The operation of this blade cleaning device is shown in FIG. When copying is completed, the photosensitive drum 1 is reversed as shown in FIG. 3(C), and then the blade 2 is retracted from the photosensitive drum 1 as shown in FIG. 3(d) to enter a standby state. Reference numeral 3 indicates residual toner adhering to the photosensitive drum 1, and the toner adhering to the blade 2 leaks out due to the reversal of the photosensitive drum 1. When the copying machine is on standby, the tip of the leaked toner 3 corresponds to the free end of the blade 2 when viewed in the normal rotation direction of the photosensitive drum 1, so when copying is restarted, the photosensitive drum 1 must be If the blade 2 is brought into pressure contact with the photosensitive drum 1 at the same time as the photosensitive drum 1 rotates, residual toner 3 will remain on the photosensitive drum 1 due to a delay in rotation time of the blade 2.

In order to solve this problem, Japanese Patent Application Laid-Open No. 58-196566
No. 2, proposed a blade cleaning device that rotates the photosensitive drum in reverse after the blade is separated from the photosensitive drum at the end of copying. The operation of this blade cleaning device will be explained with reference to FIG.
After the blade 2 is retracted from the photosensitive drum 1 as shown in (C), the photosensitive drum 1 is reversed as shown in (d) and enters a standby state. In this case, since the blade 2 is separated from the photosensitive drum when the photosensitive drum is reversed, the toner held on the blade 2 hardly ever re-adheres to the photosensitive drum 1, and only a small amount of toner is deposited on the photosensitive drum 1 as shown in FIG. toner 3 remains on the photosensitive drum 1. Of course, in the copying process, toner on the photosensitive drum 1 that has not yet reached the cleaning blade 2 remains on the photosensitive drum, but such residual toner will be omitted in the explanation of FIG. be.

As shown in FIG. 4(d), during standby, a small amount of adhered toner 3 is located upstream of the blade 2, so when the copying operation is resumed and the photosensitive drum 1 is rotated forward, the blade is removed at the same time. If the blade 2 is controlled to come into pressure contact with the photosensitive drum 1, the blade 2 will come into pressure contact with the photosensitive drum 1 while the toner 3 is still on the upstream side of the blade 2, as shown in FIG. 4(e). Therefore, the problem of toner remaining on the photosensitive drum 1, which was a problem in the blade cleaning device shown in FIG. 3, does not occur in the blade cleaning device shown in FIG. 4.

Problems to be Solved by the Invention As mentioned above, in the blade cleaning device shown in FIG. However, there was a problem in that the inside of the copying machine became dirty.

In addition, in the conventional blade cleaning device shown in FIG. 4, there is no problem of toner remaining on the photosensitive drum when the copying operation is restarted, but when the blade 2 is left in contact with the photosensitive drum 1, Since the photosensitive drum 1 is not rotated in the reverse direction, the blade 2 cannot be squeezed due to the reverse rotation of the photosensitive drum 1, resulting in a problem of poor cleaning due to paper dust from the transfer paper adhering to the tip of the blade 2. If paper dust attached to blade 2 is not removed,
There was a risk that not only cleaning would be inadequate, but also the photosensitive drum 1 would be damaged.

The present invention was developed in view of the above, and its purpose is to eliminate both poor cleaning due to paper dust adhering to the tip of the blade and internal contamination caused by toner remaining on the photoreceptor. An object of the present invention is to provide a cleaning device for a copying machine that prevents the above problems.

Means for Solving the Problems In order to solve the problems of the prior art described above, the blade cleaning device of the present invention reverses the photoreceptor for a predetermined time at the end of copying, and then retracts the free end of the blade to remove the photoreceptor from the photoreceptor. The present invention is characterized by comprising a control means for controlling the photoreceptor to further rotate in the reverse direction for a predetermined period of time.

Instead of removing the blade from the photoreceptor at the end of copying and then reversing the photoreceptor for a predetermined period of time, the blade remains away from the photoreceptor at the end of copying to end the control, and when copying is restarted, the free end of the blade is rotated after reversing the photoreceptor. It may be controlled so that it comes into pressure contact with the photoreceptor.

1-m-■ As described above, the present invention includes a method in which the free end of the blade is separated from the photoreceptor after the photoreceptor is reversed at the end of copying, and the photoreceptor is controlled to be reversed immediately thereafter or when copying is restarted. Therefore, it is possible to prevent both internal dirt caused by toner left on the photoreceptor and cleaning failure caused by paper dust adhering to the tip of the blade.

Embodiments The present invention will be explained in detail below based on embodiments shown in the drawings.

FIG. 1 shows the operation timing of the first embodiment of the present invention, and the photosensitive drum 1 is made of, for example, selenium, which may deteriorate if the cleaning blade 2 is constantly pressed against it. The blade 2 has a hardness of, for example, 65 to
It is a 90-degree polyurethane blade, and its free end is configured to be able to be pressed against the photosensitive drum by a biasing means (not shown), and can be moved from the surface of the photosensitive drum as necessary by a retracting means (not shown). It is configured to be retractable. The retraction means are
For example, it can be constructed from a solenoid or the like.

FIG. 1(a) shows the operation during copying, in which the photosensitive drum 1 rotates normally, and the blade 2 comes into pressure contact with the photosensitive drum 1 to scrape off residual toner on the photosensitive drum 1. 1st
As shown in FIG. 1(b), when the copying operation is completed, the rotation of the photosensitive drum temporarily stops, but after the rotation is stopped, as shown in FIG. 1(c), the photosensitive drum 1 remains in pressure contact with the photosensitive drum 1. Reverse time. If the photosensitive drum is reversed while the blade 2 is in pressure contact with the photosensitive drum 1 in this manner, residual toner adhering to the blade 2 will leak out as shown by reference numeral 3.

After the photosensitive drum 1 is reversed for a predetermined period of time as shown in FIG. 1(C), the blade 2 is retracted from the surface of the photosensitive drum 1 by a retracting means (not shown) as shown in FIG. 1(d). As shown in e), the photosensitive drum 1 is further rotated in reverse for a predetermined period of time, and the copying machine enters the standby state.

As shown in FIG. 1(e), since the photosensitive drum 1 is rotated in reverse again, the tip of the leaked toner 3 is located upstream of the blade 2 when viewed in the normal rotation direction of the photosensitive drum. become. Because the leaked toner 3 and the blade 2 are in such a positional relationship, even if the blade 2 is driven so as to come into pressure contact with the photosensitive drum 1 at the same time as the photosensitive drum 1 is rotated forward when copying is restarted. As shown in FIG. 1(f), at the time when the blade 2 is brought into pressure contact with the photosensitive drum 1, the leaked toner 3 is still located on the upstream side of the blade 2.

Therefore, when copying is restarted, toner is not left unwiped by the blade 2, and stains inside the copying machine caused by unwiped toner can be prevented. Further, as shown in FIG. 1(C), the blade 2 is connected to the photosensitive drum 1.
Since the photosensitive drum is rotated in the opposite direction while being in pressure contact with the photosensitive drum 1, the blade 2 can be squeezed by the photosensitive drum 1, and as a result, paper dust adhering to the tip of the blade can be scraped off.

FIG. 2 shows another embodiment of the invention, in which M
In terms of the embodiment, the steps up to FIG. 2(d) are similar to each step of the first embodiment shown in FIG. The iR mode is different from the first embodiment IIA described above in that the copying machine enters a standby state in step (d).

That is, in this embodiment, when the copying operation is restarted, the photosensitive drum 1 is first rotated in reverse for a predetermined time while the blade 2 is retracted, as shown in FIG. 2(e). As a result, the tip of the leaked toner 3 is located upstream of the blade 2, and the blade 2 is brought into pressure contact with the photosensitive drum at the same time as the photosensitive drum is rotated forward, as shown in FIG. When the blade 2 is brought into pressure contact with the photosensitive drum 1, the leaked toner 3 is removed.
is located upstream of the blade 2, so that no toner is left unwiped by the blade 2.

Further, the paper powder adhering to the blade 2 can be scraped off from the blade 2 by rotating the photosensitive drum 1 in a reverse direction while keeping the blade 2 in pressure contact with the photosensitive drum 1 as shown in the step of FIG. 2(C).

Effects of the Invention Since the cleaning device for a copying machine of the present invention is configured as detailed above, it has the effect of preventing dirt inside the machine due to toner left on the photoreceptor and cleaning failures due to paper dust adhering to the blade. play.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the operation timing of the first actual FAm of the present invention, Fig. 2 is a schematic diagram showing the operation timing of the second actual FAm of the invention, and Fig. 3 is the operational timing of the conventional device. FIG. 4 is a schematic diagram showing the operation timing of another conventional device. 1... Photosensitive drum, 2... Cleaning blade, 3... Toner.

Claims (2)

[Claims] (1) Copying is completed in a cleaning device for a copying machine that includes a blade whose free end presses against the surface of a rotatably supported photoreceptor and a retracting means for separating the free end of the blade from the photoreceptor surface. Cleaning of a copying machine characterized in that a control means is provided for controlling the free end of the blade to be separated from the photoreceptor by the retracting means after the photoreceptor is reversed for a predetermined time, and then the photoreceptor is further reversed for a predetermined time. Device. (2) Copying is completed in a copying machine cleaning device that includes a blade whose free end presses against the surface of a rotatably supported photoreceptor, and a retracting means for separating the free end of the blade from the photoreceptor surface. control so that the free end of the blade is separated from the photoreceptor by the retracting means after the photoreceptor is reversed for a predetermined time, and the free end of the blade is brought into pressure contact with the photoreceptor after the photoreceptor is reversed for a predetermined time when copying is restarted. A cleaning device for a copying machine, characterized in that a cleaning device is provided.